1 /* 2 * Copyright (C) 2016-2020 Red Hat, Inc. 3 * Copyright (C) 2005 Anthony Liguori <anthony@codemonkey.ws> 4 * 5 * Network Block Device Server Side 6 * 7 * This program is free software; you can redistribute it and/or modify 8 * it under the terms of the GNU General Public License as published by 9 * the Free Software Foundation; under version 2 of the License. 10 * 11 * This program is distributed in the hope that it will be useful, 12 * but WITHOUT ANY WARRANTY; without even the implied warranty of 13 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the 14 * GNU General Public License for more details. 15 * 16 * You should have received a copy of the GNU General Public License 17 * along with this program; if not, see <http://www.gnu.org/licenses/>. 18 */ 19 20 #include "qemu/osdep.h" 21 22 #include "block/export.h" 23 #include "qapi/error.h" 24 #include "qemu/queue.h" 25 #include "trace.h" 26 #include "nbd-internal.h" 27 #include "qemu/units.h" 28 29 #define NBD_META_ID_BASE_ALLOCATION 0 30 #define NBD_META_ID_ALLOCATION_DEPTH 1 31 /* Dirty bitmaps use 'NBD_META_ID_DIRTY_BITMAP + i', so keep this id last. */ 32 #define NBD_META_ID_DIRTY_BITMAP 2 33 34 /* 35 * NBD_MAX_BLOCK_STATUS_EXTENTS: 1 MiB of extents data. An empirical 36 * constant. If an increase is needed, note that the NBD protocol 37 * recommends no larger than 32 mb, so that the client won't consider 38 * the reply as a denial of service attack. 39 */ 40 #define NBD_MAX_BLOCK_STATUS_EXTENTS (1 * MiB / 8) 41 42 static int system_errno_to_nbd_errno(int err) 43 { 44 switch (err) { 45 case 0: 46 return NBD_SUCCESS; 47 case EPERM: 48 case EROFS: 49 return NBD_EPERM; 50 case EIO: 51 return NBD_EIO; 52 case ENOMEM: 53 return NBD_ENOMEM; 54 #ifdef EDQUOT 55 case EDQUOT: 56 #endif 57 case EFBIG: 58 case ENOSPC: 59 return NBD_ENOSPC; 60 case EOVERFLOW: 61 return NBD_EOVERFLOW; 62 case ENOTSUP: 63 #if ENOTSUP != EOPNOTSUPP 64 case EOPNOTSUPP: 65 #endif 66 return NBD_ENOTSUP; 67 case ESHUTDOWN: 68 return NBD_ESHUTDOWN; 69 case EINVAL: 70 default: 71 return NBD_EINVAL; 72 } 73 } 74 75 /* Definitions for opaque data types */ 76 77 typedef struct NBDRequestData NBDRequestData; 78 79 struct NBDRequestData { 80 QSIMPLEQ_ENTRY(NBDRequestData) entry; 81 NBDClient *client; 82 uint8_t *data; 83 bool complete; 84 }; 85 86 struct NBDExport { 87 BlockExport common; 88 89 char *name; 90 char *description; 91 uint64_t size; 92 uint16_t nbdflags; 93 QTAILQ_HEAD(, NBDClient) clients; 94 QTAILQ_ENTRY(NBDExport) next; 95 96 BlockBackend *eject_notifier_blk; 97 Notifier eject_notifier; 98 99 bool allocation_depth; 100 BdrvDirtyBitmap **export_bitmaps; 101 size_t nr_export_bitmaps; 102 }; 103 104 static QTAILQ_HEAD(, NBDExport) exports = QTAILQ_HEAD_INITIALIZER(exports); 105 106 /* NBDExportMetaContexts represents a list of contexts to be exported, 107 * as selected by NBD_OPT_SET_META_CONTEXT. Also used for 108 * NBD_OPT_LIST_META_CONTEXT. */ 109 typedef struct NBDExportMetaContexts { 110 NBDExport *exp; 111 size_t count; /* number of negotiated contexts */ 112 bool base_allocation; /* export base:allocation context (block status) */ 113 bool allocation_depth; /* export qemu:allocation-depth */ 114 bool *bitmaps; /* 115 * export qemu:dirty-bitmap:<export bitmap name>, 116 * sized by exp->nr_export_bitmaps 117 */ 118 } NBDExportMetaContexts; 119 120 struct NBDClient { 121 int refcount; 122 void (*close_fn)(NBDClient *client, bool negotiated); 123 124 NBDExport *exp; 125 QCryptoTLSCreds *tlscreds; 126 char *tlsauthz; 127 QIOChannelSocket *sioc; /* The underlying data channel */ 128 QIOChannel *ioc; /* The current I/O channel which may differ (eg TLS) */ 129 130 Coroutine *recv_coroutine; 131 132 CoMutex send_lock; 133 Coroutine *send_coroutine; 134 135 QTAILQ_ENTRY(NBDClient) next; 136 int nb_requests; 137 bool closing; 138 139 uint32_t check_align; /* If non-zero, check for aligned client requests */ 140 141 bool structured_reply; 142 NBDExportMetaContexts export_meta; 143 144 uint32_t opt; /* Current option being negotiated */ 145 uint32_t optlen; /* remaining length of data in ioc for the option being 146 negotiated now */ 147 }; 148 149 static void nbd_client_receive_next_request(NBDClient *client); 150 151 /* Basic flow for negotiation 152 153 Server Client 154 Negotiate 155 156 or 157 158 Server Client 159 Negotiate #1 160 Option 161 Negotiate #2 162 163 ---- 164 165 followed by 166 167 Server Client 168 Request 169 Response 170 Request 171 Response 172 ... 173 ... 174 Request (type == 2) 175 176 */ 177 178 static inline void set_be_option_rep(NBDOptionReply *rep, uint32_t option, 179 uint32_t type, uint32_t length) 180 { 181 stq_be_p(&rep->magic, NBD_REP_MAGIC); 182 stl_be_p(&rep->option, option); 183 stl_be_p(&rep->type, type); 184 stl_be_p(&rep->length, length); 185 } 186 187 /* Send a reply header, including length, but no payload. 188 * Return -errno on error, 0 on success. */ 189 static int nbd_negotiate_send_rep_len(NBDClient *client, uint32_t type, 190 uint32_t len, Error **errp) 191 { 192 NBDOptionReply rep; 193 194 trace_nbd_negotiate_send_rep_len(client->opt, nbd_opt_lookup(client->opt), 195 type, nbd_rep_lookup(type), len); 196 197 assert(len < NBD_MAX_BUFFER_SIZE); 198 199 set_be_option_rep(&rep, client->opt, type, len); 200 return nbd_write(client->ioc, &rep, sizeof(rep), errp); 201 } 202 203 /* Send a reply header with default 0 length. 204 * Return -errno on error, 0 on success. */ 205 static int nbd_negotiate_send_rep(NBDClient *client, uint32_t type, 206 Error **errp) 207 { 208 return nbd_negotiate_send_rep_len(client, type, 0, errp); 209 } 210 211 /* Send an error reply. 212 * Return -errno on error, 0 on success. */ 213 static int GCC_FMT_ATTR(4, 0) 214 nbd_negotiate_send_rep_verr(NBDClient *client, uint32_t type, 215 Error **errp, const char *fmt, va_list va) 216 { 217 ERRP_GUARD(); 218 g_autofree char *msg = NULL; 219 int ret; 220 size_t len; 221 222 msg = g_strdup_vprintf(fmt, va); 223 len = strlen(msg); 224 assert(len < NBD_MAX_STRING_SIZE); 225 trace_nbd_negotiate_send_rep_err(msg); 226 ret = nbd_negotiate_send_rep_len(client, type, len, errp); 227 if (ret < 0) { 228 return ret; 229 } 230 if (nbd_write(client->ioc, msg, len, errp) < 0) { 231 error_prepend(errp, "write failed (error message): "); 232 return -EIO; 233 } 234 235 return 0; 236 } 237 238 /* 239 * Return a malloc'd copy of @name suitable for use in an error reply. 240 */ 241 static char * 242 nbd_sanitize_name(const char *name) 243 { 244 if (strnlen(name, 80) < 80) { 245 return g_strdup(name); 246 } 247 /* XXX Should we also try to sanitize any control characters? */ 248 return g_strdup_printf("%.80s...", name); 249 } 250 251 /* Send an error reply. 252 * Return -errno on error, 0 on success. */ 253 static int GCC_FMT_ATTR(4, 5) 254 nbd_negotiate_send_rep_err(NBDClient *client, uint32_t type, 255 Error **errp, const char *fmt, ...) 256 { 257 va_list va; 258 int ret; 259 260 va_start(va, fmt); 261 ret = nbd_negotiate_send_rep_verr(client, type, errp, fmt, va); 262 va_end(va); 263 return ret; 264 } 265 266 /* Drop remainder of the current option, and send a reply with the 267 * given error type and message. Return -errno on read or write 268 * failure; or 0 if connection is still live. */ 269 static int GCC_FMT_ATTR(4, 0) 270 nbd_opt_vdrop(NBDClient *client, uint32_t type, Error **errp, 271 const char *fmt, va_list va) 272 { 273 int ret = nbd_drop(client->ioc, client->optlen, errp); 274 275 client->optlen = 0; 276 if (!ret) { 277 ret = nbd_negotiate_send_rep_verr(client, type, errp, fmt, va); 278 } 279 return ret; 280 } 281 282 static int GCC_FMT_ATTR(4, 5) 283 nbd_opt_drop(NBDClient *client, uint32_t type, Error **errp, 284 const char *fmt, ...) 285 { 286 int ret; 287 va_list va; 288 289 va_start(va, fmt); 290 ret = nbd_opt_vdrop(client, type, errp, fmt, va); 291 va_end(va); 292 293 return ret; 294 } 295 296 static int GCC_FMT_ATTR(3, 4) 297 nbd_opt_invalid(NBDClient *client, Error **errp, const char *fmt, ...) 298 { 299 int ret; 300 va_list va; 301 302 va_start(va, fmt); 303 ret = nbd_opt_vdrop(client, NBD_REP_ERR_INVALID, errp, fmt, va); 304 va_end(va); 305 306 return ret; 307 } 308 309 /* Read size bytes from the unparsed payload of the current option. 310 * If @check_nul, require that no NUL bytes appear in buffer. 311 * Return -errno on I/O error, 0 if option was completely handled by 312 * sending a reply about inconsistent lengths, or 1 on success. */ 313 static int nbd_opt_read(NBDClient *client, void *buffer, size_t size, 314 bool check_nul, Error **errp) 315 { 316 if (size > client->optlen) { 317 return nbd_opt_invalid(client, errp, 318 "Inconsistent lengths in option %s", 319 nbd_opt_lookup(client->opt)); 320 } 321 client->optlen -= size; 322 if (qio_channel_read_all(client->ioc, buffer, size, errp) < 0) { 323 return -EIO; 324 } 325 326 if (check_nul && strnlen(buffer, size) != size) { 327 return nbd_opt_invalid(client, errp, 328 "Unexpected embedded NUL in option %s", 329 nbd_opt_lookup(client->opt)); 330 } 331 return 1; 332 } 333 334 /* Drop size bytes from the unparsed payload of the current option. 335 * Return -errno on I/O error, 0 if option was completely handled by 336 * sending a reply about inconsistent lengths, or 1 on success. */ 337 static int nbd_opt_skip(NBDClient *client, size_t size, Error **errp) 338 { 339 if (size > client->optlen) { 340 return nbd_opt_invalid(client, errp, 341 "Inconsistent lengths in option %s", 342 nbd_opt_lookup(client->opt)); 343 } 344 client->optlen -= size; 345 return nbd_drop(client->ioc, size, errp) < 0 ? -EIO : 1; 346 } 347 348 /* nbd_opt_read_name 349 * 350 * Read a string with the format: 351 * uint32_t len (<= NBD_MAX_STRING_SIZE) 352 * len bytes string (not 0-terminated) 353 * 354 * On success, @name will be allocated. 355 * If @length is non-null, it will be set to the actual string length. 356 * 357 * Return -errno on I/O error, 0 if option was completely handled by 358 * sending a reply about inconsistent lengths, or 1 on success. 359 */ 360 static int nbd_opt_read_name(NBDClient *client, char **name, uint32_t *length, 361 Error **errp) 362 { 363 int ret; 364 uint32_t len; 365 g_autofree char *local_name = NULL; 366 367 *name = NULL; 368 ret = nbd_opt_read(client, &len, sizeof(len), false, errp); 369 if (ret <= 0) { 370 return ret; 371 } 372 len = cpu_to_be32(len); 373 374 if (len > NBD_MAX_STRING_SIZE) { 375 return nbd_opt_invalid(client, errp, 376 "Invalid name length: %" PRIu32, len); 377 } 378 379 local_name = g_malloc(len + 1); 380 ret = nbd_opt_read(client, local_name, len, true, errp); 381 if (ret <= 0) { 382 return ret; 383 } 384 local_name[len] = '\0'; 385 386 if (length) { 387 *length = len; 388 } 389 *name = g_steal_pointer(&local_name); 390 391 return 1; 392 } 393 394 /* Send a single NBD_REP_SERVER reply to NBD_OPT_LIST, including payload. 395 * Return -errno on error, 0 on success. */ 396 static int nbd_negotiate_send_rep_list(NBDClient *client, NBDExport *exp, 397 Error **errp) 398 { 399 ERRP_GUARD(); 400 size_t name_len, desc_len; 401 uint32_t len; 402 const char *name = exp->name ? exp->name : ""; 403 const char *desc = exp->description ? exp->description : ""; 404 QIOChannel *ioc = client->ioc; 405 int ret; 406 407 trace_nbd_negotiate_send_rep_list(name, desc); 408 name_len = strlen(name); 409 desc_len = strlen(desc); 410 assert(name_len <= NBD_MAX_STRING_SIZE && desc_len <= NBD_MAX_STRING_SIZE); 411 len = name_len + desc_len + sizeof(len); 412 ret = nbd_negotiate_send_rep_len(client, NBD_REP_SERVER, len, errp); 413 if (ret < 0) { 414 return ret; 415 } 416 417 len = cpu_to_be32(name_len); 418 if (nbd_write(ioc, &len, sizeof(len), errp) < 0) { 419 error_prepend(errp, "write failed (name length): "); 420 return -EINVAL; 421 } 422 423 if (nbd_write(ioc, name, name_len, errp) < 0) { 424 error_prepend(errp, "write failed (name buffer): "); 425 return -EINVAL; 426 } 427 428 if (nbd_write(ioc, desc, desc_len, errp) < 0) { 429 error_prepend(errp, "write failed (description buffer): "); 430 return -EINVAL; 431 } 432 433 return 0; 434 } 435 436 /* Process the NBD_OPT_LIST command, with a potential series of replies. 437 * Return -errno on error, 0 on success. */ 438 static int nbd_negotiate_handle_list(NBDClient *client, Error **errp) 439 { 440 NBDExport *exp; 441 assert(client->opt == NBD_OPT_LIST); 442 443 /* For each export, send a NBD_REP_SERVER reply. */ 444 QTAILQ_FOREACH(exp, &exports, next) { 445 if (nbd_negotiate_send_rep_list(client, exp, errp)) { 446 return -EINVAL; 447 } 448 } 449 /* Finish with a NBD_REP_ACK. */ 450 return nbd_negotiate_send_rep(client, NBD_REP_ACK, errp); 451 } 452 453 static void nbd_check_meta_export(NBDClient *client) 454 { 455 if (client->exp != client->export_meta.exp) { 456 client->export_meta.count = 0; 457 } 458 } 459 460 /* Send a reply to NBD_OPT_EXPORT_NAME. 461 * Return -errno on error, 0 on success. */ 462 static int nbd_negotiate_handle_export_name(NBDClient *client, bool no_zeroes, 463 Error **errp) 464 { 465 ERRP_GUARD(); 466 g_autofree char *name = NULL; 467 char buf[NBD_REPLY_EXPORT_NAME_SIZE] = ""; 468 size_t len; 469 int ret; 470 uint16_t myflags; 471 472 /* Client sends: 473 [20 .. xx] export name (length bytes) 474 Server replies: 475 [ 0 .. 7] size 476 [ 8 .. 9] export flags 477 [10 .. 133] reserved (0) [unless no_zeroes] 478 */ 479 trace_nbd_negotiate_handle_export_name(); 480 if (client->optlen > NBD_MAX_STRING_SIZE) { 481 error_setg(errp, "Bad length received"); 482 return -EINVAL; 483 } 484 name = g_malloc(client->optlen + 1); 485 if (nbd_read(client->ioc, name, client->optlen, "export name", errp) < 0) { 486 return -EIO; 487 } 488 name[client->optlen] = '\0'; 489 client->optlen = 0; 490 491 trace_nbd_negotiate_handle_export_name_request(name); 492 493 client->exp = nbd_export_find(name); 494 if (!client->exp) { 495 error_setg(errp, "export not found"); 496 return -EINVAL; 497 } 498 499 myflags = client->exp->nbdflags; 500 if (client->structured_reply) { 501 myflags |= NBD_FLAG_SEND_DF; 502 } 503 trace_nbd_negotiate_new_style_size_flags(client->exp->size, myflags); 504 stq_be_p(buf, client->exp->size); 505 stw_be_p(buf + 8, myflags); 506 len = no_zeroes ? 10 : sizeof(buf); 507 ret = nbd_write(client->ioc, buf, len, errp); 508 if (ret < 0) { 509 error_prepend(errp, "write failed: "); 510 return ret; 511 } 512 513 QTAILQ_INSERT_TAIL(&client->exp->clients, client, next); 514 blk_exp_ref(&client->exp->common); 515 nbd_check_meta_export(client); 516 517 return 0; 518 } 519 520 /* Send a single NBD_REP_INFO, with a buffer @buf of @length bytes. 521 * The buffer does NOT include the info type prefix. 522 * Return -errno on error, 0 if ready to send more. */ 523 static int nbd_negotiate_send_info(NBDClient *client, 524 uint16_t info, uint32_t length, void *buf, 525 Error **errp) 526 { 527 int rc; 528 529 trace_nbd_negotiate_send_info(info, nbd_info_lookup(info), length); 530 rc = nbd_negotiate_send_rep_len(client, NBD_REP_INFO, 531 sizeof(info) + length, errp); 532 if (rc < 0) { 533 return rc; 534 } 535 info = cpu_to_be16(info); 536 if (nbd_write(client->ioc, &info, sizeof(info), errp) < 0) { 537 return -EIO; 538 } 539 if (nbd_write(client->ioc, buf, length, errp) < 0) { 540 return -EIO; 541 } 542 return 0; 543 } 544 545 /* nbd_reject_length: Handle any unexpected payload. 546 * @fatal requests that we quit talking to the client, even if we are able 547 * to successfully send an error reply. 548 * Return: 549 * -errno transmission error occurred or @fatal was requested, errp is set 550 * 0 error message successfully sent to client, errp is not set 551 */ 552 static int nbd_reject_length(NBDClient *client, bool fatal, Error **errp) 553 { 554 int ret; 555 556 assert(client->optlen); 557 ret = nbd_opt_invalid(client, errp, "option '%s' has unexpected length", 558 nbd_opt_lookup(client->opt)); 559 if (fatal && !ret) { 560 error_setg(errp, "option '%s' has unexpected length", 561 nbd_opt_lookup(client->opt)); 562 return -EINVAL; 563 } 564 return ret; 565 } 566 567 /* Handle NBD_OPT_INFO and NBD_OPT_GO. 568 * Return -errno on error, 0 if ready for next option, and 1 to move 569 * into transmission phase. */ 570 static int nbd_negotiate_handle_info(NBDClient *client, Error **errp) 571 { 572 int rc; 573 g_autofree char *name = NULL; 574 NBDExport *exp; 575 uint16_t requests; 576 uint16_t request; 577 uint32_t namelen = 0; 578 bool sendname = false; 579 bool blocksize = false; 580 uint32_t sizes[3]; 581 char buf[sizeof(uint64_t) + sizeof(uint16_t)]; 582 uint32_t check_align = 0; 583 uint16_t myflags; 584 585 /* Client sends: 586 4 bytes: L, name length (can be 0) 587 L bytes: export name 588 2 bytes: N, number of requests (can be 0) 589 N * 2 bytes: N requests 590 */ 591 rc = nbd_opt_read_name(client, &name, &namelen, errp); 592 if (rc <= 0) { 593 return rc; 594 } 595 trace_nbd_negotiate_handle_export_name_request(name); 596 597 rc = nbd_opt_read(client, &requests, sizeof(requests), false, errp); 598 if (rc <= 0) { 599 return rc; 600 } 601 requests = be16_to_cpu(requests); 602 trace_nbd_negotiate_handle_info_requests(requests); 603 while (requests--) { 604 rc = nbd_opt_read(client, &request, sizeof(request), false, errp); 605 if (rc <= 0) { 606 return rc; 607 } 608 request = be16_to_cpu(request); 609 trace_nbd_negotiate_handle_info_request(request, 610 nbd_info_lookup(request)); 611 /* We care about NBD_INFO_NAME and NBD_INFO_BLOCK_SIZE; 612 * everything else is either a request we don't know or 613 * something we send regardless of request */ 614 switch (request) { 615 case NBD_INFO_NAME: 616 sendname = true; 617 break; 618 case NBD_INFO_BLOCK_SIZE: 619 blocksize = true; 620 break; 621 } 622 } 623 if (client->optlen) { 624 return nbd_reject_length(client, false, errp); 625 } 626 627 exp = nbd_export_find(name); 628 if (!exp) { 629 g_autofree char *sane_name = nbd_sanitize_name(name); 630 631 return nbd_negotiate_send_rep_err(client, NBD_REP_ERR_UNKNOWN, 632 errp, "export '%s' not present", 633 sane_name); 634 } 635 636 /* Don't bother sending NBD_INFO_NAME unless client requested it */ 637 if (sendname) { 638 rc = nbd_negotiate_send_info(client, NBD_INFO_NAME, namelen, name, 639 errp); 640 if (rc < 0) { 641 return rc; 642 } 643 } 644 645 /* Send NBD_INFO_DESCRIPTION only if available, regardless of 646 * client request */ 647 if (exp->description) { 648 size_t len = strlen(exp->description); 649 650 assert(len <= NBD_MAX_STRING_SIZE); 651 rc = nbd_negotiate_send_info(client, NBD_INFO_DESCRIPTION, 652 len, exp->description, errp); 653 if (rc < 0) { 654 return rc; 655 } 656 } 657 658 /* Send NBD_INFO_BLOCK_SIZE always, but tweak the minimum size 659 * according to whether the client requested it, and according to 660 * whether this is OPT_INFO or OPT_GO. */ 661 /* minimum - 1 for back-compat, or actual if client will obey it. */ 662 if (client->opt == NBD_OPT_INFO || blocksize) { 663 check_align = sizes[0] = blk_get_request_alignment(exp->common.blk); 664 } else { 665 sizes[0] = 1; 666 } 667 assert(sizes[0] <= NBD_MAX_BUFFER_SIZE); 668 /* preferred - Hard-code to 4096 for now. 669 * TODO: is blk_bs(blk)->bl.opt_transfer appropriate? */ 670 sizes[1] = MAX(4096, sizes[0]); 671 /* maximum - At most 32M, but smaller as appropriate. */ 672 sizes[2] = MIN(blk_get_max_transfer(exp->common.blk), NBD_MAX_BUFFER_SIZE); 673 trace_nbd_negotiate_handle_info_block_size(sizes[0], sizes[1], sizes[2]); 674 sizes[0] = cpu_to_be32(sizes[0]); 675 sizes[1] = cpu_to_be32(sizes[1]); 676 sizes[2] = cpu_to_be32(sizes[2]); 677 rc = nbd_negotiate_send_info(client, NBD_INFO_BLOCK_SIZE, 678 sizeof(sizes), sizes, errp); 679 if (rc < 0) { 680 return rc; 681 } 682 683 /* Send NBD_INFO_EXPORT always */ 684 myflags = exp->nbdflags; 685 if (client->structured_reply) { 686 myflags |= NBD_FLAG_SEND_DF; 687 } 688 trace_nbd_negotiate_new_style_size_flags(exp->size, myflags); 689 stq_be_p(buf, exp->size); 690 stw_be_p(buf + 8, myflags); 691 rc = nbd_negotiate_send_info(client, NBD_INFO_EXPORT, 692 sizeof(buf), buf, errp); 693 if (rc < 0) { 694 return rc; 695 } 696 697 /* 698 * If the client is just asking for NBD_OPT_INFO, but forgot to 699 * request block sizes in a situation that would impact 700 * performance, then return an error. But for NBD_OPT_GO, we 701 * tolerate all clients, regardless of alignments. 702 */ 703 if (client->opt == NBD_OPT_INFO && !blocksize && 704 blk_get_request_alignment(exp->common.blk) > 1) { 705 return nbd_negotiate_send_rep_err(client, 706 NBD_REP_ERR_BLOCK_SIZE_REQD, 707 errp, 708 "request NBD_INFO_BLOCK_SIZE to " 709 "use this export"); 710 } 711 712 /* Final reply */ 713 rc = nbd_negotiate_send_rep(client, NBD_REP_ACK, errp); 714 if (rc < 0) { 715 return rc; 716 } 717 718 if (client->opt == NBD_OPT_GO) { 719 client->exp = exp; 720 client->check_align = check_align; 721 QTAILQ_INSERT_TAIL(&client->exp->clients, client, next); 722 blk_exp_ref(&client->exp->common); 723 nbd_check_meta_export(client); 724 rc = 1; 725 } 726 return rc; 727 } 728 729 730 /* Handle NBD_OPT_STARTTLS. Return NULL to drop connection, or else the 731 * new channel for all further (now-encrypted) communication. */ 732 static QIOChannel *nbd_negotiate_handle_starttls(NBDClient *client, 733 Error **errp) 734 { 735 QIOChannel *ioc; 736 QIOChannelTLS *tioc; 737 struct NBDTLSHandshakeData data = { 0 }; 738 739 assert(client->opt == NBD_OPT_STARTTLS); 740 741 trace_nbd_negotiate_handle_starttls(); 742 ioc = client->ioc; 743 744 if (nbd_negotiate_send_rep(client, NBD_REP_ACK, errp) < 0) { 745 return NULL; 746 } 747 748 tioc = qio_channel_tls_new_server(ioc, 749 client->tlscreds, 750 client->tlsauthz, 751 errp); 752 if (!tioc) { 753 return NULL; 754 } 755 756 qio_channel_set_name(QIO_CHANNEL(tioc), "nbd-server-tls"); 757 trace_nbd_negotiate_handle_starttls_handshake(); 758 data.loop = g_main_loop_new(g_main_context_default(), FALSE); 759 qio_channel_tls_handshake(tioc, 760 nbd_tls_handshake, 761 &data, 762 NULL, 763 NULL); 764 765 if (!data.complete) { 766 g_main_loop_run(data.loop); 767 } 768 g_main_loop_unref(data.loop); 769 if (data.error) { 770 object_unref(OBJECT(tioc)); 771 error_propagate(errp, data.error); 772 return NULL; 773 } 774 775 return QIO_CHANNEL(tioc); 776 } 777 778 /* nbd_negotiate_send_meta_context 779 * 780 * Send one chunk of reply to NBD_OPT_{LIST,SET}_META_CONTEXT 781 * 782 * For NBD_OPT_LIST_META_CONTEXT @context_id is ignored, 0 is used instead. 783 */ 784 static int nbd_negotiate_send_meta_context(NBDClient *client, 785 const char *context, 786 uint32_t context_id, 787 Error **errp) 788 { 789 NBDOptionReplyMetaContext opt; 790 struct iovec iov[] = { 791 {.iov_base = &opt, .iov_len = sizeof(opt)}, 792 {.iov_base = (void *)context, .iov_len = strlen(context)} 793 }; 794 795 assert(iov[1].iov_len <= NBD_MAX_STRING_SIZE); 796 if (client->opt == NBD_OPT_LIST_META_CONTEXT) { 797 context_id = 0; 798 } 799 800 trace_nbd_negotiate_meta_query_reply(context, context_id); 801 set_be_option_rep(&opt.h, client->opt, NBD_REP_META_CONTEXT, 802 sizeof(opt) - sizeof(opt.h) + iov[1].iov_len); 803 stl_be_p(&opt.context_id, context_id); 804 805 return qio_channel_writev_all(client->ioc, iov, 2, errp) < 0 ? -EIO : 0; 806 } 807 808 /* 809 * Return true if @query matches @pattern, or if @query is empty when 810 * the @client is performing _LIST_. 811 */ 812 static bool nbd_meta_empty_or_pattern(NBDClient *client, const char *pattern, 813 const char *query) 814 { 815 if (!*query) { 816 trace_nbd_negotiate_meta_query_parse("empty"); 817 return client->opt == NBD_OPT_LIST_META_CONTEXT; 818 } 819 if (strcmp(query, pattern) == 0) { 820 trace_nbd_negotiate_meta_query_parse(pattern); 821 return true; 822 } 823 trace_nbd_negotiate_meta_query_skip("pattern not matched"); 824 return false; 825 } 826 827 /* 828 * Return true and adjust @str in place if it begins with @prefix. 829 */ 830 static bool nbd_strshift(const char **str, const char *prefix) 831 { 832 size_t len = strlen(prefix); 833 834 if (strncmp(*str, prefix, len) == 0) { 835 *str += len; 836 return true; 837 } 838 return false; 839 } 840 841 /* nbd_meta_base_query 842 * 843 * Handle queries to 'base' namespace. For now, only the base:allocation 844 * context is available. Return true if @query has been handled. 845 */ 846 static bool nbd_meta_base_query(NBDClient *client, NBDExportMetaContexts *meta, 847 const char *query) 848 { 849 if (!nbd_strshift(&query, "base:")) { 850 return false; 851 } 852 trace_nbd_negotiate_meta_query_parse("base:"); 853 854 if (nbd_meta_empty_or_pattern(client, "allocation", query)) { 855 meta->base_allocation = true; 856 } 857 return true; 858 } 859 860 /* nbd_meta_qemu_query 861 * 862 * Handle queries to 'qemu' namespace. For now, only the qemu:dirty-bitmap: 863 * and qemu:allocation-depth contexts are available. Return true if @query 864 * has been handled. 865 */ 866 static bool nbd_meta_qemu_query(NBDClient *client, NBDExportMetaContexts *meta, 867 const char *query) 868 { 869 size_t i; 870 871 if (!nbd_strshift(&query, "qemu:")) { 872 return false; 873 } 874 trace_nbd_negotiate_meta_query_parse("qemu:"); 875 876 if (!*query) { 877 if (client->opt == NBD_OPT_LIST_META_CONTEXT) { 878 meta->allocation_depth = meta->exp->allocation_depth; 879 memset(meta->bitmaps, 1, meta->exp->nr_export_bitmaps); 880 } 881 trace_nbd_negotiate_meta_query_parse("empty"); 882 return true; 883 } 884 885 if (strcmp(query, "allocation-depth") == 0) { 886 trace_nbd_negotiate_meta_query_parse("allocation-depth"); 887 meta->allocation_depth = meta->exp->allocation_depth; 888 return true; 889 } 890 891 if (nbd_strshift(&query, "dirty-bitmap:")) { 892 trace_nbd_negotiate_meta_query_parse("dirty-bitmap:"); 893 if (!*query) { 894 if (client->opt == NBD_OPT_LIST_META_CONTEXT) { 895 memset(meta->bitmaps, 1, meta->exp->nr_export_bitmaps); 896 } 897 trace_nbd_negotiate_meta_query_parse("empty"); 898 return true; 899 } 900 901 for (i = 0; i < meta->exp->nr_export_bitmaps; i++) { 902 const char *bm_name; 903 904 bm_name = bdrv_dirty_bitmap_name(meta->exp->export_bitmaps[i]); 905 if (strcmp(bm_name, query) == 0) { 906 meta->bitmaps[i] = true; 907 trace_nbd_negotiate_meta_query_parse(query); 908 return true; 909 } 910 } 911 trace_nbd_negotiate_meta_query_skip("no dirty-bitmap match"); 912 return true; 913 } 914 915 trace_nbd_negotiate_meta_query_skip("unknown qemu context"); 916 return true; 917 } 918 919 /* nbd_negotiate_meta_query 920 * 921 * Parse namespace name and call corresponding function to parse body of the 922 * query. 923 * 924 * The only supported namespaces are 'base' and 'qemu'. 925 * 926 * Return -errno on I/O error, 0 if option was completely handled by 927 * sending a reply about inconsistent lengths, or 1 on success. */ 928 static int nbd_negotiate_meta_query(NBDClient *client, 929 NBDExportMetaContexts *meta, Error **errp) 930 { 931 int ret; 932 g_autofree char *query = NULL; 933 uint32_t len; 934 935 ret = nbd_opt_read(client, &len, sizeof(len), false, errp); 936 if (ret <= 0) { 937 return ret; 938 } 939 len = cpu_to_be32(len); 940 941 if (len > NBD_MAX_STRING_SIZE) { 942 trace_nbd_negotiate_meta_query_skip("length too long"); 943 return nbd_opt_skip(client, len, errp); 944 } 945 946 query = g_malloc(len + 1); 947 ret = nbd_opt_read(client, query, len, true, errp); 948 if (ret <= 0) { 949 return ret; 950 } 951 query[len] = '\0'; 952 953 if (nbd_meta_base_query(client, meta, query)) { 954 return 1; 955 } 956 if (nbd_meta_qemu_query(client, meta, query)) { 957 return 1; 958 } 959 960 trace_nbd_negotiate_meta_query_skip("unknown namespace"); 961 return 1; 962 } 963 964 /* nbd_negotiate_meta_queries 965 * Handle NBD_OPT_LIST_META_CONTEXT and NBD_OPT_SET_META_CONTEXT 966 * 967 * Return -errno on I/O error, or 0 if option was completely handled. */ 968 static int nbd_negotiate_meta_queries(NBDClient *client, 969 NBDExportMetaContexts *meta, Error **errp) 970 { 971 int ret; 972 g_autofree char *export_name = NULL; 973 g_autofree bool *bitmaps = NULL; 974 NBDExportMetaContexts local_meta = {0}; 975 uint32_t nb_queries; 976 size_t i; 977 size_t count = 0; 978 979 if (!client->structured_reply) { 980 return nbd_opt_invalid(client, errp, 981 "request option '%s' when structured reply " 982 "is not negotiated", 983 nbd_opt_lookup(client->opt)); 984 } 985 986 if (client->opt == NBD_OPT_LIST_META_CONTEXT) { 987 /* Only change the caller's meta on SET. */ 988 meta = &local_meta; 989 } 990 991 g_free(meta->bitmaps); 992 memset(meta, 0, sizeof(*meta)); 993 994 ret = nbd_opt_read_name(client, &export_name, NULL, errp); 995 if (ret <= 0) { 996 return ret; 997 } 998 999 meta->exp = nbd_export_find(export_name); 1000 if (meta->exp == NULL) { 1001 g_autofree char *sane_name = nbd_sanitize_name(export_name); 1002 1003 return nbd_opt_drop(client, NBD_REP_ERR_UNKNOWN, errp, 1004 "export '%s' not present", sane_name); 1005 } 1006 meta->bitmaps = g_new0(bool, meta->exp->nr_export_bitmaps); 1007 if (client->opt == NBD_OPT_LIST_META_CONTEXT) { 1008 bitmaps = meta->bitmaps; 1009 } 1010 1011 ret = nbd_opt_read(client, &nb_queries, sizeof(nb_queries), false, errp); 1012 if (ret <= 0) { 1013 return ret; 1014 } 1015 nb_queries = cpu_to_be32(nb_queries); 1016 trace_nbd_negotiate_meta_context(nbd_opt_lookup(client->opt), 1017 export_name, nb_queries); 1018 1019 if (client->opt == NBD_OPT_LIST_META_CONTEXT && !nb_queries) { 1020 /* enable all known contexts */ 1021 meta->base_allocation = true; 1022 meta->allocation_depth = meta->exp->allocation_depth; 1023 memset(meta->bitmaps, 1, meta->exp->nr_export_bitmaps); 1024 } else { 1025 for (i = 0; i < nb_queries; ++i) { 1026 ret = nbd_negotiate_meta_query(client, meta, errp); 1027 if (ret <= 0) { 1028 return ret; 1029 } 1030 } 1031 } 1032 1033 if (meta->base_allocation) { 1034 ret = nbd_negotiate_send_meta_context(client, "base:allocation", 1035 NBD_META_ID_BASE_ALLOCATION, 1036 errp); 1037 if (ret < 0) { 1038 return ret; 1039 } 1040 count++; 1041 } 1042 1043 if (meta->allocation_depth) { 1044 ret = nbd_negotiate_send_meta_context(client, "qemu:allocation-depth", 1045 NBD_META_ID_ALLOCATION_DEPTH, 1046 errp); 1047 if (ret < 0) { 1048 return ret; 1049 } 1050 count++; 1051 } 1052 1053 for (i = 0; i < meta->exp->nr_export_bitmaps; i++) { 1054 const char *bm_name; 1055 g_autofree char *context = NULL; 1056 1057 if (!meta->bitmaps[i]) { 1058 continue; 1059 } 1060 1061 bm_name = bdrv_dirty_bitmap_name(meta->exp->export_bitmaps[i]); 1062 context = g_strdup_printf("qemu:dirty-bitmap:%s", bm_name); 1063 1064 ret = nbd_negotiate_send_meta_context(client, context, 1065 NBD_META_ID_DIRTY_BITMAP + i, 1066 errp); 1067 if (ret < 0) { 1068 return ret; 1069 } 1070 count++; 1071 } 1072 1073 ret = nbd_negotiate_send_rep(client, NBD_REP_ACK, errp); 1074 if (ret == 0) { 1075 meta->count = count; 1076 } 1077 1078 return ret; 1079 } 1080 1081 /* nbd_negotiate_options 1082 * Process all NBD_OPT_* client option commands, during fixed newstyle 1083 * negotiation. 1084 * Return: 1085 * -errno on error, errp is set 1086 * 0 on successful negotiation, errp is not set 1087 * 1 if client sent NBD_OPT_ABORT, i.e. on valid disconnect, 1088 * errp is not set 1089 */ 1090 static int nbd_negotiate_options(NBDClient *client, Error **errp) 1091 { 1092 uint32_t flags; 1093 bool fixedNewstyle = false; 1094 bool no_zeroes = false; 1095 1096 /* Client sends: 1097 [ 0 .. 3] client flags 1098 1099 Then we loop until NBD_OPT_EXPORT_NAME or NBD_OPT_GO: 1100 [ 0 .. 7] NBD_OPTS_MAGIC 1101 [ 8 .. 11] NBD option 1102 [12 .. 15] Data length 1103 ... Rest of request 1104 1105 [ 0 .. 7] NBD_OPTS_MAGIC 1106 [ 8 .. 11] Second NBD option 1107 [12 .. 15] Data length 1108 ... Rest of request 1109 */ 1110 1111 if (nbd_read32(client->ioc, &flags, "flags", errp) < 0) { 1112 return -EIO; 1113 } 1114 trace_nbd_negotiate_options_flags(flags); 1115 if (flags & NBD_FLAG_C_FIXED_NEWSTYLE) { 1116 fixedNewstyle = true; 1117 flags &= ~NBD_FLAG_C_FIXED_NEWSTYLE; 1118 } 1119 if (flags & NBD_FLAG_C_NO_ZEROES) { 1120 no_zeroes = true; 1121 flags &= ~NBD_FLAG_C_NO_ZEROES; 1122 } 1123 if (flags != 0) { 1124 error_setg(errp, "Unknown client flags 0x%" PRIx32 " received", flags); 1125 return -EINVAL; 1126 } 1127 1128 while (1) { 1129 int ret; 1130 uint32_t option, length; 1131 uint64_t magic; 1132 1133 if (nbd_read64(client->ioc, &magic, "opts magic", errp) < 0) { 1134 return -EINVAL; 1135 } 1136 trace_nbd_negotiate_options_check_magic(magic); 1137 if (magic != NBD_OPTS_MAGIC) { 1138 error_setg(errp, "Bad magic received"); 1139 return -EINVAL; 1140 } 1141 1142 if (nbd_read32(client->ioc, &option, "option", errp) < 0) { 1143 return -EINVAL; 1144 } 1145 client->opt = option; 1146 1147 if (nbd_read32(client->ioc, &length, "option length", errp) < 0) { 1148 return -EINVAL; 1149 } 1150 assert(!client->optlen); 1151 client->optlen = length; 1152 1153 if (length > NBD_MAX_BUFFER_SIZE) { 1154 error_setg(errp, "len (%" PRIu32" ) is larger than max len (%u)", 1155 length, NBD_MAX_BUFFER_SIZE); 1156 return -EINVAL; 1157 } 1158 1159 trace_nbd_negotiate_options_check_option(option, 1160 nbd_opt_lookup(option)); 1161 if (client->tlscreds && 1162 client->ioc == (QIOChannel *)client->sioc) { 1163 QIOChannel *tioc; 1164 if (!fixedNewstyle) { 1165 error_setg(errp, "Unsupported option 0x%" PRIx32, option); 1166 return -EINVAL; 1167 } 1168 switch (option) { 1169 case NBD_OPT_STARTTLS: 1170 if (length) { 1171 /* Unconditionally drop the connection if the client 1172 * can't start a TLS negotiation correctly */ 1173 return nbd_reject_length(client, true, errp); 1174 } 1175 tioc = nbd_negotiate_handle_starttls(client, errp); 1176 if (!tioc) { 1177 return -EIO; 1178 } 1179 ret = 0; 1180 object_unref(OBJECT(client->ioc)); 1181 client->ioc = QIO_CHANNEL(tioc); 1182 break; 1183 1184 case NBD_OPT_EXPORT_NAME: 1185 /* No way to return an error to client, so drop connection */ 1186 error_setg(errp, "Option 0x%x not permitted before TLS", 1187 option); 1188 return -EINVAL; 1189 1190 default: 1191 /* Let the client keep trying, unless they asked to 1192 * quit. Always try to give an error back to the 1193 * client; but when replying to OPT_ABORT, be aware 1194 * that the client may hang up before receiving the 1195 * error, in which case we are fine ignoring the 1196 * resulting EPIPE. */ 1197 ret = nbd_opt_drop(client, NBD_REP_ERR_TLS_REQD, 1198 option == NBD_OPT_ABORT ? NULL : errp, 1199 "Option 0x%" PRIx32 1200 " not permitted before TLS", option); 1201 if (option == NBD_OPT_ABORT) { 1202 return 1; 1203 } 1204 break; 1205 } 1206 } else if (fixedNewstyle) { 1207 switch (option) { 1208 case NBD_OPT_LIST: 1209 if (length) { 1210 ret = nbd_reject_length(client, false, errp); 1211 } else { 1212 ret = nbd_negotiate_handle_list(client, errp); 1213 } 1214 break; 1215 1216 case NBD_OPT_ABORT: 1217 /* NBD spec says we must try to reply before 1218 * disconnecting, but that we must also tolerate 1219 * guests that don't wait for our reply. */ 1220 nbd_negotiate_send_rep(client, NBD_REP_ACK, NULL); 1221 return 1; 1222 1223 case NBD_OPT_EXPORT_NAME: 1224 return nbd_negotiate_handle_export_name(client, no_zeroes, 1225 errp); 1226 1227 case NBD_OPT_INFO: 1228 case NBD_OPT_GO: 1229 ret = nbd_negotiate_handle_info(client, errp); 1230 if (ret == 1) { 1231 assert(option == NBD_OPT_GO); 1232 return 0; 1233 } 1234 break; 1235 1236 case NBD_OPT_STARTTLS: 1237 if (length) { 1238 ret = nbd_reject_length(client, false, errp); 1239 } else if (client->tlscreds) { 1240 ret = nbd_negotiate_send_rep_err(client, 1241 NBD_REP_ERR_INVALID, errp, 1242 "TLS already enabled"); 1243 } else { 1244 ret = nbd_negotiate_send_rep_err(client, 1245 NBD_REP_ERR_POLICY, errp, 1246 "TLS not configured"); 1247 } 1248 break; 1249 1250 case NBD_OPT_STRUCTURED_REPLY: 1251 if (length) { 1252 ret = nbd_reject_length(client, false, errp); 1253 } else if (client->structured_reply) { 1254 ret = nbd_negotiate_send_rep_err( 1255 client, NBD_REP_ERR_INVALID, errp, 1256 "structured reply already negotiated"); 1257 } else { 1258 ret = nbd_negotiate_send_rep(client, NBD_REP_ACK, errp); 1259 client->structured_reply = true; 1260 } 1261 break; 1262 1263 case NBD_OPT_LIST_META_CONTEXT: 1264 case NBD_OPT_SET_META_CONTEXT: 1265 ret = nbd_negotiate_meta_queries(client, &client->export_meta, 1266 errp); 1267 break; 1268 1269 default: 1270 ret = nbd_opt_drop(client, NBD_REP_ERR_UNSUP, errp, 1271 "Unsupported option %" PRIu32 " (%s)", 1272 option, nbd_opt_lookup(option)); 1273 break; 1274 } 1275 } else { 1276 /* 1277 * If broken new-style we should drop the connection 1278 * for anything except NBD_OPT_EXPORT_NAME 1279 */ 1280 switch (option) { 1281 case NBD_OPT_EXPORT_NAME: 1282 return nbd_negotiate_handle_export_name(client, no_zeroes, 1283 errp); 1284 1285 default: 1286 error_setg(errp, "Unsupported option %" PRIu32 " (%s)", 1287 option, nbd_opt_lookup(option)); 1288 return -EINVAL; 1289 } 1290 } 1291 if (ret < 0) { 1292 return ret; 1293 } 1294 } 1295 } 1296 1297 /* nbd_negotiate 1298 * Return: 1299 * -errno on error, errp is set 1300 * 0 on successful negotiation, errp is not set 1301 * 1 if client sent NBD_OPT_ABORT, i.e. on valid disconnect, 1302 * errp is not set 1303 */ 1304 static coroutine_fn int nbd_negotiate(NBDClient *client, Error **errp) 1305 { 1306 ERRP_GUARD(); 1307 char buf[NBD_OLDSTYLE_NEGOTIATE_SIZE] = ""; 1308 int ret; 1309 1310 /* Old style negotiation header, no room for options 1311 [ 0 .. 7] passwd ("NBDMAGIC") 1312 [ 8 .. 15] magic (NBD_CLIENT_MAGIC) 1313 [16 .. 23] size 1314 [24 .. 27] export flags (zero-extended) 1315 [28 .. 151] reserved (0) 1316 1317 New style negotiation header, client can send options 1318 [ 0 .. 7] passwd ("NBDMAGIC") 1319 [ 8 .. 15] magic (NBD_OPTS_MAGIC) 1320 [16 .. 17] server flags (0) 1321 ....options sent, ending in NBD_OPT_EXPORT_NAME or NBD_OPT_GO.... 1322 */ 1323 1324 qio_channel_set_blocking(client->ioc, false, NULL); 1325 1326 trace_nbd_negotiate_begin(); 1327 memcpy(buf, "NBDMAGIC", 8); 1328 1329 stq_be_p(buf + 8, NBD_OPTS_MAGIC); 1330 stw_be_p(buf + 16, NBD_FLAG_FIXED_NEWSTYLE | NBD_FLAG_NO_ZEROES); 1331 1332 if (nbd_write(client->ioc, buf, 18, errp) < 0) { 1333 error_prepend(errp, "write failed: "); 1334 return -EINVAL; 1335 } 1336 ret = nbd_negotiate_options(client, errp); 1337 if (ret != 0) { 1338 if (ret < 0) { 1339 error_prepend(errp, "option negotiation failed: "); 1340 } 1341 return ret; 1342 } 1343 1344 /* Attach the channel to the same AioContext as the export */ 1345 if (client->exp && client->exp->common.ctx) { 1346 qio_channel_attach_aio_context(client->ioc, client->exp->common.ctx); 1347 } 1348 1349 assert(!client->optlen); 1350 trace_nbd_negotiate_success(); 1351 1352 return 0; 1353 } 1354 1355 static int nbd_receive_request(QIOChannel *ioc, NBDRequest *request, 1356 Error **errp) 1357 { 1358 uint8_t buf[NBD_REQUEST_SIZE]; 1359 uint32_t magic; 1360 int ret; 1361 1362 ret = nbd_read(ioc, buf, sizeof(buf), "request", errp); 1363 if (ret < 0) { 1364 return ret; 1365 } 1366 1367 /* Request 1368 [ 0 .. 3] magic (NBD_REQUEST_MAGIC) 1369 [ 4 .. 5] flags (NBD_CMD_FLAG_FUA, ...) 1370 [ 6 .. 7] type (NBD_CMD_READ, ...) 1371 [ 8 .. 15] handle 1372 [16 .. 23] from 1373 [24 .. 27] len 1374 */ 1375 1376 magic = ldl_be_p(buf); 1377 request->flags = lduw_be_p(buf + 4); 1378 request->type = lduw_be_p(buf + 6); 1379 request->handle = ldq_be_p(buf + 8); 1380 request->from = ldq_be_p(buf + 16); 1381 request->len = ldl_be_p(buf + 24); 1382 1383 trace_nbd_receive_request(magic, request->flags, request->type, 1384 request->from, request->len); 1385 1386 if (magic != NBD_REQUEST_MAGIC) { 1387 error_setg(errp, "invalid magic (got 0x%" PRIx32 ")", magic); 1388 return -EINVAL; 1389 } 1390 return 0; 1391 } 1392 1393 #define MAX_NBD_REQUESTS 16 1394 1395 void nbd_client_get(NBDClient *client) 1396 { 1397 client->refcount++; 1398 } 1399 1400 void nbd_client_put(NBDClient *client) 1401 { 1402 if (--client->refcount == 0) { 1403 /* The last reference should be dropped by client->close, 1404 * which is called by client_close. 1405 */ 1406 assert(client->closing); 1407 1408 qio_channel_detach_aio_context(client->ioc); 1409 object_unref(OBJECT(client->sioc)); 1410 object_unref(OBJECT(client->ioc)); 1411 if (client->tlscreds) { 1412 object_unref(OBJECT(client->tlscreds)); 1413 } 1414 g_free(client->tlsauthz); 1415 if (client->exp) { 1416 QTAILQ_REMOVE(&client->exp->clients, client, next); 1417 blk_exp_unref(&client->exp->common); 1418 } 1419 g_free(client->export_meta.bitmaps); 1420 g_free(client); 1421 } 1422 } 1423 1424 static void client_close(NBDClient *client, bool negotiated) 1425 { 1426 if (client->closing) { 1427 return; 1428 } 1429 1430 client->closing = true; 1431 1432 /* Force requests to finish. They will drop their own references, 1433 * then we'll close the socket and free the NBDClient. 1434 */ 1435 qio_channel_shutdown(client->ioc, QIO_CHANNEL_SHUTDOWN_BOTH, 1436 NULL); 1437 1438 /* Also tell the client, so that they release their reference. */ 1439 if (client->close_fn) { 1440 client->close_fn(client, negotiated); 1441 } 1442 } 1443 1444 static NBDRequestData *nbd_request_get(NBDClient *client) 1445 { 1446 NBDRequestData *req; 1447 1448 assert(client->nb_requests <= MAX_NBD_REQUESTS - 1); 1449 client->nb_requests++; 1450 1451 req = g_new0(NBDRequestData, 1); 1452 nbd_client_get(client); 1453 req->client = client; 1454 return req; 1455 } 1456 1457 static void nbd_request_put(NBDRequestData *req) 1458 { 1459 NBDClient *client = req->client; 1460 1461 if (req->data) { 1462 qemu_vfree(req->data); 1463 } 1464 g_free(req); 1465 1466 client->nb_requests--; 1467 nbd_client_receive_next_request(client); 1468 1469 nbd_client_put(client); 1470 } 1471 1472 static void blk_aio_attached(AioContext *ctx, void *opaque) 1473 { 1474 NBDExport *exp = opaque; 1475 NBDClient *client; 1476 1477 trace_nbd_blk_aio_attached(exp->name, ctx); 1478 1479 exp->common.ctx = ctx; 1480 1481 QTAILQ_FOREACH(client, &exp->clients, next) { 1482 qio_channel_attach_aio_context(client->ioc, ctx); 1483 if (client->recv_coroutine) { 1484 aio_co_schedule(ctx, client->recv_coroutine); 1485 } 1486 if (client->send_coroutine) { 1487 aio_co_schedule(ctx, client->send_coroutine); 1488 } 1489 } 1490 } 1491 1492 static void blk_aio_detach(void *opaque) 1493 { 1494 NBDExport *exp = opaque; 1495 NBDClient *client; 1496 1497 trace_nbd_blk_aio_detach(exp->name, exp->common.ctx); 1498 1499 QTAILQ_FOREACH(client, &exp->clients, next) { 1500 qio_channel_detach_aio_context(client->ioc); 1501 } 1502 1503 exp->common.ctx = NULL; 1504 } 1505 1506 static void nbd_eject_notifier(Notifier *n, void *data) 1507 { 1508 NBDExport *exp = container_of(n, NBDExport, eject_notifier); 1509 1510 blk_exp_request_shutdown(&exp->common); 1511 } 1512 1513 void nbd_export_set_on_eject_blk(BlockExport *exp, BlockBackend *blk) 1514 { 1515 NBDExport *nbd_exp = container_of(exp, NBDExport, common); 1516 assert(exp->drv == &blk_exp_nbd); 1517 assert(nbd_exp->eject_notifier_blk == NULL); 1518 1519 blk_ref(blk); 1520 nbd_exp->eject_notifier_blk = blk; 1521 nbd_exp->eject_notifier.notify = nbd_eject_notifier; 1522 blk_add_remove_bs_notifier(blk, &nbd_exp->eject_notifier); 1523 } 1524 1525 static int nbd_export_create(BlockExport *blk_exp, BlockExportOptions *exp_args, 1526 Error **errp) 1527 { 1528 NBDExport *exp = container_of(blk_exp, NBDExport, common); 1529 BlockExportOptionsNbd *arg = &exp_args->u.nbd; 1530 BlockBackend *blk = blk_exp->blk; 1531 int64_t size; 1532 uint64_t perm, shared_perm; 1533 bool readonly = !exp_args->writable; 1534 bool shared = !exp_args->writable; 1535 strList *bitmaps; 1536 size_t i; 1537 int ret; 1538 1539 assert(exp_args->type == BLOCK_EXPORT_TYPE_NBD); 1540 1541 if (!nbd_server_is_running()) { 1542 error_setg(errp, "NBD server not running"); 1543 return -EINVAL; 1544 } 1545 1546 if (!arg->has_name) { 1547 arg->name = exp_args->node_name; 1548 } 1549 1550 if (strlen(arg->name) > NBD_MAX_STRING_SIZE) { 1551 error_setg(errp, "export name '%s' too long", arg->name); 1552 return -EINVAL; 1553 } 1554 1555 if (arg->description && strlen(arg->description) > NBD_MAX_STRING_SIZE) { 1556 error_setg(errp, "description '%s' too long", arg->description); 1557 return -EINVAL; 1558 } 1559 1560 if (nbd_export_find(arg->name)) { 1561 error_setg(errp, "NBD server already has export named '%s'", arg->name); 1562 return -EEXIST; 1563 } 1564 1565 size = blk_getlength(blk); 1566 if (size < 0) { 1567 error_setg_errno(errp, -size, 1568 "Failed to determine the NBD export's length"); 1569 return size; 1570 } 1571 1572 /* Don't allow resize while the NBD server is running, otherwise we don't 1573 * care what happens with the node. */ 1574 blk_get_perm(blk, &perm, &shared_perm); 1575 ret = blk_set_perm(blk, perm, shared_perm & ~BLK_PERM_RESIZE, errp); 1576 if (ret < 0) { 1577 return ret; 1578 } 1579 1580 QTAILQ_INIT(&exp->clients); 1581 exp->name = g_strdup(arg->name); 1582 exp->description = g_strdup(arg->description); 1583 exp->nbdflags = (NBD_FLAG_HAS_FLAGS | NBD_FLAG_SEND_FLUSH | 1584 NBD_FLAG_SEND_FUA | NBD_FLAG_SEND_CACHE); 1585 if (readonly) { 1586 exp->nbdflags |= NBD_FLAG_READ_ONLY; 1587 if (shared) { 1588 exp->nbdflags |= NBD_FLAG_CAN_MULTI_CONN; 1589 } 1590 } else { 1591 exp->nbdflags |= (NBD_FLAG_SEND_TRIM | NBD_FLAG_SEND_WRITE_ZEROES | 1592 NBD_FLAG_SEND_FAST_ZERO); 1593 } 1594 exp->size = QEMU_ALIGN_DOWN(size, BDRV_SECTOR_SIZE); 1595 1596 for (bitmaps = arg->bitmaps; bitmaps; bitmaps = bitmaps->next) { 1597 exp->nr_export_bitmaps++; 1598 } 1599 exp->export_bitmaps = g_new0(BdrvDirtyBitmap *, exp->nr_export_bitmaps); 1600 for (i = 0, bitmaps = arg->bitmaps; bitmaps; 1601 i++, bitmaps = bitmaps->next) { 1602 const char *bitmap = bitmaps->value; 1603 BlockDriverState *bs = blk_bs(blk); 1604 BdrvDirtyBitmap *bm = NULL; 1605 1606 while (bs) { 1607 bm = bdrv_find_dirty_bitmap(bs, bitmap); 1608 if (bm != NULL) { 1609 break; 1610 } 1611 1612 bs = bdrv_filter_or_cow_bs(bs); 1613 } 1614 1615 if (bm == NULL) { 1616 ret = -ENOENT; 1617 error_setg(errp, "Bitmap '%s' is not found", bitmap); 1618 goto fail; 1619 } 1620 1621 if (bdrv_dirty_bitmap_check(bm, BDRV_BITMAP_ALLOW_RO, errp)) { 1622 ret = -EINVAL; 1623 goto fail; 1624 } 1625 1626 if (readonly && bdrv_is_writable(bs) && 1627 bdrv_dirty_bitmap_enabled(bm)) { 1628 ret = -EINVAL; 1629 error_setg(errp, 1630 "Enabled bitmap '%s' incompatible with readonly export", 1631 bitmap); 1632 goto fail; 1633 } 1634 1635 exp->export_bitmaps[i] = bm; 1636 assert(strlen(bitmap) <= BDRV_BITMAP_MAX_NAME_SIZE); 1637 } 1638 1639 /* Mark bitmaps busy in a separate loop, to simplify roll-back concerns. */ 1640 for (i = 0; i < exp->nr_export_bitmaps; i++) { 1641 bdrv_dirty_bitmap_set_busy(exp->export_bitmaps[i], true); 1642 } 1643 1644 exp->allocation_depth = arg->allocation_depth; 1645 1646 blk_add_aio_context_notifier(blk, blk_aio_attached, blk_aio_detach, exp); 1647 1648 QTAILQ_INSERT_TAIL(&exports, exp, next); 1649 1650 return 0; 1651 1652 fail: 1653 g_free(exp->export_bitmaps); 1654 g_free(exp->name); 1655 g_free(exp->description); 1656 return ret; 1657 } 1658 1659 NBDExport *nbd_export_find(const char *name) 1660 { 1661 NBDExport *exp; 1662 QTAILQ_FOREACH(exp, &exports, next) { 1663 if (strcmp(name, exp->name) == 0) { 1664 return exp; 1665 } 1666 } 1667 1668 return NULL; 1669 } 1670 1671 AioContext * 1672 nbd_export_aio_context(NBDExport *exp) 1673 { 1674 return exp->common.ctx; 1675 } 1676 1677 static void nbd_export_request_shutdown(BlockExport *blk_exp) 1678 { 1679 NBDExport *exp = container_of(blk_exp, NBDExport, common); 1680 NBDClient *client, *next; 1681 1682 blk_exp_ref(&exp->common); 1683 /* 1684 * TODO: Should we expand QMP NbdServerRemoveNode enum to allow a 1685 * close mode that stops advertising the export to new clients but 1686 * still permits existing clients to run to completion? Because of 1687 * that possibility, nbd_export_close() can be called more than 1688 * once on an export. 1689 */ 1690 QTAILQ_FOREACH_SAFE(client, &exp->clients, next, next) { 1691 client_close(client, true); 1692 } 1693 if (exp->name) { 1694 g_free(exp->name); 1695 exp->name = NULL; 1696 QTAILQ_REMOVE(&exports, exp, next); 1697 } 1698 blk_exp_unref(&exp->common); 1699 } 1700 1701 static void nbd_export_delete(BlockExport *blk_exp) 1702 { 1703 size_t i; 1704 NBDExport *exp = container_of(blk_exp, NBDExport, common); 1705 1706 assert(exp->name == NULL); 1707 assert(QTAILQ_EMPTY(&exp->clients)); 1708 1709 g_free(exp->description); 1710 exp->description = NULL; 1711 1712 if (exp->common.blk) { 1713 if (exp->eject_notifier_blk) { 1714 notifier_remove(&exp->eject_notifier); 1715 blk_unref(exp->eject_notifier_blk); 1716 } 1717 blk_remove_aio_context_notifier(exp->common.blk, blk_aio_attached, 1718 blk_aio_detach, exp); 1719 } 1720 1721 for (i = 0; i < exp->nr_export_bitmaps; i++) { 1722 bdrv_dirty_bitmap_set_busy(exp->export_bitmaps[i], false); 1723 } 1724 } 1725 1726 const BlockExportDriver blk_exp_nbd = { 1727 .type = BLOCK_EXPORT_TYPE_NBD, 1728 .instance_size = sizeof(NBDExport), 1729 .create = nbd_export_create, 1730 .delete = nbd_export_delete, 1731 .request_shutdown = nbd_export_request_shutdown, 1732 }; 1733 1734 static int coroutine_fn nbd_co_send_iov(NBDClient *client, struct iovec *iov, 1735 unsigned niov, Error **errp) 1736 { 1737 int ret; 1738 1739 g_assert(qemu_in_coroutine()); 1740 qemu_co_mutex_lock(&client->send_lock); 1741 client->send_coroutine = qemu_coroutine_self(); 1742 1743 ret = qio_channel_writev_all(client->ioc, iov, niov, errp) < 0 ? -EIO : 0; 1744 1745 client->send_coroutine = NULL; 1746 qemu_co_mutex_unlock(&client->send_lock); 1747 1748 return ret; 1749 } 1750 1751 static inline void set_be_simple_reply(NBDSimpleReply *reply, uint64_t error, 1752 uint64_t handle) 1753 { 1754 stl_be_p(&reply->magic, NBD_SIMPLE_REPLY_MAGIC); 1755 stl_be_p(&reply->error, error); 1756 stq_be_p(&reply->handle, handle); 1757 } 1758 1759 static int nbd_co_send_simple_reply(NBDClient *client, 1760 uint64_t handle, 1761 uint32_t error, 1762 void *data, 1763 size_t len, 1764 Error **errp) 1765 { 1766 NBDSimpleReply reply; 1767 int nbd_err = system_errno_to_nbd_errno(error); 1768 struct iovec iov[] = { 1769 {.iov_base = &reply, .iov_len = sizeof(reply)}, 1770 {.iov_base = data, .iov_len = len} 1771 }; 1772 1773 trace_nbd_co_send_simple_reply(handle, nbd_err, nbd_err_lookup(nbd_err), 1774 len); 1775 set_be_simple_reply(&reply, nbd_err, handle); 1776 1777 return nbd_co_send_iov(client, iov, len ? 2 : 1, errp); 1778 } 1779 1780 static inline void set_be_chunk(NBDStructuredReplyChunk *chunk, uint16_t flags, 1781 uint16_t type, uint64_t handle, uint32_t length) 1782 { 1783 stl_be_p(&chunk->magic, NBD_STRUCTURED_REPLY_MAGIC); 1784 stw_be_p(&chunk->flags, flags); 1785 stw_be_p(&chunk->type, type); 1786 stq_be_p(&chunk->handle, handle); 1787 stl_be_p(&chunk->length, length); 1788 } 1789 1790 static int coroutine_fn nbd_co_send_structured_done(NBDClient *client, 1791 uint64_t handle, 1792 Error **errp) 1793 { 1794 NBDStructuredReplyChunk chunk; 1795 struct iovec iov[] = { 1796 {.iov_base = &chunk, .iov_len = sizeof(chunk)}, 1797 }; 1798 1799 trace_nbd_co_send_structured_done(handle); 1800 set_be_chunk(&chunk, NBD_REPLY_FLAG_DONE, NBD_REPLY_TYPE_NONE, handle, 0); 1801 1802 return nbd_co_send_iov(client, iov, 1, errp); 1803 } 1804 1805 static int coroutine_fn nbd_co_send_structured_read(NBDClient *client, 1806 uint64_t handle, 1807 uint64_t offset, 1808 void *data, 1809 size_t size, 1810 bool final, 1811 Error **errp) 1812 { 1813 NBDStructuredReadData chunk; 1814 struct iovec iov[] = { 1815 {.iov_base = &chunk, .iov_len = sizeof(chunk)}, 1816 {.iov_base = data, .iov_len = size} 1817 }; 1818 1819 assert(size); 1820 trace_nbd_co_send_structured_read(handle, offset, data, size); 1821 set_be_chunk(&chunk.h, final ? NBD_REPLY_FLAG_DONE : 0, 1822 NBD_REPLY_TYPE_OFFSET_DATA, handle, 1823 sizeof(chunk) - sizeof(chunk.h) + size); 1824 stq_be_p(&chunk.offset, offset); 1825 1826 return nbd_co_send_iov(client, iov, 2, errp); 1827 } 1828 1829 static int coroutine_fn nbd_co_send_structured_error(NBDClient *client, 1830 uint64_t handle, 1831 uint32_t error, 1832 const char *msg, 1833 Error **errp) 1834 { 1835 NBDStructuredError chunk; 1836 int nbd_err = system_errno_to_nbd_errno(error); 1837 struct iovec iov[] = { 1838 {.iov_base = &chunk, .iov_len = sizeof(chunk)}, 1839 {.iov_base = (char *)msg, .iov_len = msg ? strlen(msg) : 0}, 1840 }; 1841 1842 assert(nbd_err); 1843 trace_nbd_co_send_structured_error(handle, nbd_err, 1844 nbd_err_lookup(nbd_err), msg ? msg : ""); 1845 set_be_chunk(&chunk.h, NBD_REPLY_FLAG_DONE, NBD_REPLY_TYPE_ERROR, handle, 1846 sizeof(chunk) - sizeof(chunk.h) + iov[1].iov_len); 1847 stl_be_p(&chunk.error, nbd_err); 1848 stw_be_p(&chunk.message_length, iov[1].iov_len); 1849 1850 return nbd_co_send_iov(client, iov, 1 + !!iov[1].iov_len, errp); 1851 } 1852 1853 /* Do a sparse read and send the structured reply to the client. 1854 * Returns -errno if sending fails. bdrv_block_status_above() failure is 1855 * reported to the client, at which point this function succeeds. 1856 */ 1857 static int coroutine_fn nbd_co_send_sparse_read(NBDClient *client, 1858 uint64_t handle, 1859 uint64_t offset, 1860 uint8_t *data, 1861 size_t size, 1862 Error **errp) 1863 { 1864 int ret = 0; 1865 NBDExport *exp = client->exp; 1866 size_t progress = 0; 1867 1868 while (progress < size) { 1869 int64_t pnum; 1870 int status = bdrv_block_status_above(blk_bs(exp->common.blk), NULL, 1871 offset + progress, 1872 size - progress, &pnum, NULL, 1873 NULL); 1874 bool final; 1875 1876 if (status < 0) { 1877 char *msg = g_strdup_printf("unable to check for holes: %s", 1878 strerror(-status)); 1879 1880 ret = nbd_co_send_structured_error(client, handle, -status, msg, 1881 errp); 1882 g_free(msg); 1883 return ret; 1884 } 1885 assert(pnum && pnum <= size - progress); 1886 final = progress + pnum == size; 1887 if (status & BDRV_BLOCK_ZERO) { 1888 NBDStructuredReadHole chunk; 1889 struct iovec iov[] = { 1890 {.iov_base = &chunk, .iov_len = sizeof(chunk)}, 1891 }; 1892 1893 trace_nbd_co_send_structured_read_hole(handle, offset + progress, 1894 pnum); 1895 set_be_chunk(&chunk.h, final ? NBD_REPLY_FLAG_DONE : 0, 1896 NBD_REPLY_TYPE_OFFSET_HOLE, 1897 handle, sizeof(chunk) - sizeof(chunk.h)); 1898 stq_be_p(&chunk.offset, offset + progress); 1899 stl_be_p(&chunk.length, pnum); 1900 ret = nbd_co_send_iov(client, iov, 1, errp); 1901 } else { 1902 ret = blk_pread(exp->common.blk, offset + progress, 1903 data + progress, pnum); 1904 if (ret < 0) { 1905 error_setg_errno(errp, -ret, "reading from file failed"); 1906 break; 1907 } 1908 ret = nbd_co_send_structured_read(client, handle, offset + progress, 1909 data + progress, pnum, final, 1910 errp); 1911 } 1912 1913 if (ret < 0) { 1914 break; 1915 } 1916 progress += pnum; 1917 } 1918 return ret; 1919 } 1920 1921 typedef struct NBDExtentArray { 1922 NBDExtent *extents; 1923 unsigned int nb_alloc; 1924 unsigned int count; 1925 uint64_t total_length; 1926 bool can_add; 1927 bool converted_to_be; 1928 } NBDExtentArray; 1929 1930 static NBDExtentArray *nbd_extent_array_new(unsigned int nb_alloc) 1931 { 1932 NBDExtentArray *ea = g_new0(NBDExtentArray, 1); 1933 1934 ea->nb_alloc = nb_alloc; 1935 ea->extents = g_new(NBDExtent, nb_alloc); 1936 ea->can_add = true; 1937 1938 return ea; 1939 } 1940 1941 static void nbd_extent_array_free(NBDExtentArray *ea) 1942 { 1943 g_free(ea->extents); 1944 g_free(ea); 1945 } 1946 G_DEFINE_AUTOPTR_CLEANUP_FUNC(NBDExtentArray, nbd_extent_array_free); 1947 1948 /* Further modifications of the array after conversion are abandoned */ 1949 static void nbd_extent_array_convert_to_be(NBDExtentArray *ea) 1950 { 1951 int i; 1952 1953 assert(!ea->converted_to_be); 1954 ea->can_add = false; 1955 ea->converted_to_be = true; 1956 1957 for (i = 0; i < ea->count; i++) { 1958 ea->extents[i].flags = cpu_to_be32(ea->extents[i].flags); 1959 ea->extents[i].length = cpu_to_be32(ea->extents[i].length); 1960 } 1961 } 1962 1963 /* 1964 * Add extent to NBDExtentArray. If extent can't be added (no available space), 1965 * return -1. 1966 * For safety, when returning -1 for the first time, .can_add is set to false, 1967 * further call to nbd_extent_array_add() will crash. 1968 * (to avoid the situation, when after failing to add an extent (returned -1), 1969 * user miss this failure and add another extent, which is successfully added 1970 * (array is full, but new extent may be squashed into the last one), then we 1971 * have invalid array with skipped extent) 1972 */ 1973 static int nbd_extent_array_add(NBDExtentArray *ea, 1974 uint32_t length, uint32_t flags) 1975 { 1976 assert(ea->can_add); 1977 1978 if (!length) { 1979 return 0; 1980 } 1981 1982 /* Extend previous extent if flags are the same */ 1983 if (ea->count > 0 && flags == ea->extents[ea->count - 1].flags) { 1984 uint64_t sum = (uint64_t)length + ea->extents[ea->count - 1].length; 1985 1986 if (sum <= UINT32_MAX) { 1987 ea->extents[ea->count - 1].length = sum; 1988 ea->total_length += length; 1989 return 0; 1990 } 1991 } 1992 1993 if (ea->count >= ea->nb_alloc) { 1994 ea->can_add = false; 1995 return -1; 1996 } 1997 1998 ea->total_length += length; 1999 ea->extents[ea->count] = (NBDExtent) {.length = length, .flags = flags}; 2000 ea->count++; 2001 2002 return 0; 2003 } 2004 2005 static int blockstatus_to_extents(BlockDriverState *bs, uint64_t offset, 2006 uint64_t bytes, NBDExtentArray *ea) 2007 { 2008 while (bytes) { 2009 uint32_t flags; 2010 int64_t num; 2011 int ret = bdrv_block_status_above(bs, NULL, offset, bytes, &num, 2012 NULL, NULL); 2013 2014 if (ret < 0) { 2015 return ret; 2016 } 2017 2018 flags = (ret & BDRV_BLOCK_ALLOCATED ? 0 : NBD_STATE_HOLE) | 2019 (ret & BDRV_BLOCK_ZERO ? NBD_STATE_ZERO : 0); 2020 2021 if (nbd_extent_array_add(ea, num, flags) < 0) { 2022 return 0; 2023 } 2024 2025 offset += num; 2026 bytes -= num; 2027 } 2028 2029 return 0; 2030 } 2031 2032 static int blockalloc_to_extents(BlockDriverState *bs, uint64_t offset, 2033 uint64_t bytes, NBDExtentArray *ea) 2034 { 2035 while (bytes) { 2036 int64_t num; 2037 int ret = bdrv_is_allocated_above(bs, NULL, false, offset, bytes, 2038 &num); 2039 2040 if (ret < 0) { 2041 return ret; 2042 } 2043 2044 if (nbd_extent_array_add(ea, num, ret) < 0) { 2045 return 0; 2046 } 2047 2048 offset += num; 2049 bytes -= num; 2050 } 2051 2052 return 0; 2053 } 2054 2055 /* 2056 * nbd_co_send_extents 2057 * 2058 * @ea is converted to BE by the function 2059 * @last controls whether NBD_REPLY_FLAG_DONE is sent. 2060 */ 2061 static int nbd_co_send_extents(NBDClient *client, uint64_t handle, 2062 NBDExtentArray *ea, 2063 bool last, uint32_t context_id, Error **errp) 2064 { 2065 NBDStructuredMeta chunk; 2066 struct iovec iov[] = { 2067 {.iov_base = &chunk, .iov_len = sizeof(chunk)}, 2068 {.iov_base = ea->extents, .iov_len = ea->count * sizeof(ea->extents[0])} 2069 }; 2070 2071 nbd_extent_array_convert_to_be(ea); 2072 2073 trace_nbd_co_send_extents(handle, ea->count, context_id, ea->total_length, 2074 last); 2075 set_be_chunk(&chunk.h, last ? NBD_REPLY_FLAG_DONE : 0, 2076 NBD_REPLY_TYPE_BLOCK_STATUS, 2077 handle, sizeof(chunk) - sizeof(chunk.h) + iov[1].iov_len); 2078 stl_be_p(&chunk.context_id, context_id); 2079 2080 return nbd_co_send_iov(client, iov, 2, errp); 2081 } 2082 2083 /* Get block status from the exported device and send it to the client */ 2084 static int nbd_co_send_block_status(NBDClient *client, uint64_t handle, 2085 BlockDriverState *bs, uint64_t offset, 2086 uint32_t length, bool dont_fragment, 2087 bool last, uint32_t context_id, 2088 Error **errp) 2089 { 2090 int ret; 2091 unsigned int nb_extents = dont_fragment ? 1 : NBD_MAX_BLOCK_STATUS_EXTENTS; 2092 g_autoptr(NBDExtentArray) ea = nbd_extent_array_new(nb_extents); 2093 2094 if (context_id == NBD_META_ID_BASE_ALLOCATION) { 2095 ret = blockstatus_to_extents(bs, offset, length, ea); 2096 } else { 2097 ret = blockalloc_to_extents(bs, offset, length, ea); 2098 } 2099 if (ret < 0) { 2100 return nbd_co_send_structured_error( 2101 client, handle, -ret, "can't get block status", errp); 2102 } 2103 2104 return nbd_co_send_extents(client, handle, ea, last, context_id, errp); 2105 } 2106 2107 /* Populate @ea from a dirty bitmap. */ 2108 static void bitmap_to_extents(BdrvDirtyBitmap *bitmap, 2109 uint64_t offset, uint64_t length, 2110 NBDExtentArray *es) 2111 { 2112 int64_t start, dirty_start, dirty_count; 2113 int64_t end = offset + length; 2114 bool full = false; 2115 2116 bdrv_dirty_bitmap_lock(bitmap); 2117 2118 for (start = offset; 2119 bdrv_dirty_bitmap_next_dirty_area(bitmap, start, end, INT32_MAX, 2120 &dirty_start, &dirty_count); 2121 start = dirty_start + dirty_count) 2122 { 2123 if ((nbd_extent_array_add(es, dirty_start - start, 0) < 0) || 2124 (nbd_extent_array_add(es, dirty_count, NBD_STATE_DIRTY) < 0)) 2125 { 2126 full = true; 2127 break; 2128 } 2129 } 2130 2131 if (!full) { 2132 /* last non dirty extent */ 2133 nbd_extent_array_add(es, end - start, 0); 2134 } 2135 2136 bdrv_dirty_bitmap_unlock(bitmap); 2137 } 2138 2139 static int nbd_co_send_bitmap(NBDClient *client, uint64_t handle, 2140 BdrvDirtyBitmap *bitmap, uint64_t offset, 2141 uint32_t length, bool dont_fragment, bool last, 2142 uint32_t context_id, Error **errp) 2143 { 2144 unsigned int nb_extents = dont_fragment ? 1 : NBD_MAX_BLOCK_STATUS_EXTENTS; 2145 g_autoptr(NBDExtentArray) ea = nbd_extent_array_new(nb_extents); 2146 2147 bitmap_to_extents(bitmap, offset, length, ea); 2148 2149 return nbd_co_send_extents(client, handle, ea, last, context_id, errp); 2150 } 2151 2152 /* nbd_co_receive_request 2153 * Collect a client request. Return 0 if request looks valid, -EIO to drop 2154 * connection right away, and any other negative value to report an error to 2155 * the client (although the caller may still need to disconnect after reporting 2156 * the error). 2157 */ 2158 static int nbd_co_receive_request(NBDRequestData *req, NBDRequest *request, 2159 Error **errp) 2160 { 2161 NBDClient *client = req->client; 2162 int valid_flags; 2163 2164 g_assert(qemu_in_coroutine()); 2165 assert(client->recv_coroutine == qemu_coroutine_self()); 2166 if (nbd_receive_request(client->ioc, request, errp) < 0) { 2167 return -EIO; 2168 } 2169 2170 trace_nbd_co_receive_request_decode_type(request->handle, request->type, 2171 nbd_cmd_lookup(request->type)); 2172 2173 if (request->type != NBD_CMD_WRITE) { 2174 /* No payload, we are ready to read the next request. */ 2175 req->complete = true; 2176 } 2177 2178 if (request->type == NBD_CMD_DISC) { 2179 /* Special case: we're going to disconnect without a reply, 2180 * whether or not flags, from, or len are bogus */ 2181 return -EIO; 2182 } 2183 2184 if (request->type == NBD_CMD_READ || request->type == NBD_CMD_WRITE || 2185 request->type == NBD_CMD_CACHE) 2186 { 2187 if (request->len > NBD_MAX_BUFFER_SIZE) { 2188 error_setg(errp, "len (%" PRIu32" ) is larger than max len (%u)", 2189 request->len, NBD_MAX_BUFFER_SIZE); 2190 return -EINVAL; 2191 } 2192 2193 if (request->type != NBD_CMD_CACHE) { 2194 req->data = blk_try_blockalign(client->exp->common.blk, 2195 request->len); 2196 if (req->data == NULL) { 2197 error_setg(errp, "No memory"); 2198 return -ENOMEM; 2199 } 2200 } 2201 } 2202 2203 if (request->type == NBD_CMD_WRITE) { 2204 if (nbd_read(client->ioc, req->data, request->len, "CMD_WRITE data", 2205 errp) < 0) 2206 { 2207 return -EIO; 2208 } 2209 req->complete = true; 2210 2211 trace_nbd_co_receive_request_payload_received(request->handle, 2212 request->len); 2213 } 2214 2215 /* Sanity checks. */ 2216 if (client->exp->nbdflags & NBD_FLAG_READ_ONLY && 2217 (request->type == NBD_CMD_WRITE || 2218 request->type == NBD_CMD_WRITE_ZEROES || 2219 request->type == NBD_CMD_TRIM)) { 2220 error_setg(errp, "Export is read-only"); 2221 return -EROFS; 2222 } 2223 if (request->from > client->exp->size || 2224 request->len > client->exp->size - request->from) { 2225 error_setg(errp, "operation past EOF; From: %" PRIu64 ", Len: %" PRIu32 2226 ", Size: %" PRIu64, request->from, request->len, 2227 client->exp->size); 2228 return (request->type == NBD_CMD_WRITE || 2229 request->type == NBD_CMD_WRITE_ZEROES) ? -ENOSPC : -EINVAL; 2230 } 2231 if (client->check_align && !QEMU_IS_ALIGNED(request->from | request->len, 2232 client->check_align)) { 2233 /* 2234 * The block layer gracefully handles unaligned requests, but 2235 * it's still worth tracing client non-compliance 2236 */ 2237 trace_nbd_co_receive_align_compliance(nbd_cmd_lookup(request->type), 2238 request->from, 2239 request->len, 2240 client->check_align); 2241 } 2242 valid_flags = NBD_CMD_FLAG_FUA; 2243 if (request->type == NBD_CMD_READ && client->structured_reply) { 2244 valid_flags |= NBD_CMD_FLAG_DF; 2245 } else if (request->type == NBD_CMD_WRITE_ZEROES) { 2246 valid_flags |= NBD_CMD_FLAG_NO_HOLE | NBD_CMD_FLAG_FAST_ZERO; 2247 } else if (request->type == NBD_CMD_BLOCK_STATUS) { 2248 valid_flags |= NBD_CMD_FLAG_REQ_ONE; 2249 } 2250 if (request->flags & ~valid_flags) { 2251 error_setg(errp, "unsupported flags for command %s (got 0x%x)", 2252 nbd_cmd_lookup(request->type), request->flags); 2253 return -EINVAL; 2254 } 2255 2256 return 0; 2257 } 2258 2259 /* Send simple reply without a payload, or a structured error 2260 * @error_msg is ignored if @ret >= 0 2261 * Returns 0 if connection is still live, -errno on failure to talk to client 2262 */ 2263 static coroutine_fn int nbd_send_generic_reply(NBDClient *client, 2264 uint64_t handle, 2265 int ret, 2266 const char *error_msg, 2267 Error **errp) 2268 { 2269 if (client->structured_reply && ret < 0) { 2270 return nbd_co_send_structured_error(client, handle, -ret, error_msg, 2271 errp); 2272 } else { 2273 return nbd_co_send_simple_reply(client, handle, ret < 0 ? -ret : 0, 2274 NULL, 0, errp); 2275 } 2276 } 2277 2278 /* Handle NBD_CMD_READ request. 2279 * Return -errno if sending fails. Other errors are reported directly to the 2280 * client as an error reply. */ 2281 static coroutine_fn int nbd_do_cmd_read(NBDClient *client, NBDRequest *request, 2282 uint8_t *data, Error **errp) 2283 { 2284 int ret; 2285 NBDExport *exp = client->exp; 2286 2287 assert(request->type == NBD_CMD_READ); 2288 2289 /* XXX: NBD Protocol only documents use of FUA with WRITE */ 2290 if (request->flags & NBD_CMD_FLAG_FUA) { 2291 ret = blk_co_flush(exp->common.blk); 2292 if (ret < 0) { 2293 return nbd_send_generic_reply(client, request->handle, ret, 2294 "flush failed", errp); 2295 } 2296 } 2297 2298 if (client->structured_reply && !(request->flags & NBD_CMD_FLAG_DF) && 2299 request->len) 2300 { 2301 return nbd_co_send_sparse_read(client, request->handle, request->from, 2302 data, request->len, errp); 2303 } 2304 2305 ret = blk_pread(exp->common.blk, request->from, data, request->len); 2306 if (ret < 0) { 2307 return nbd_send_generic_reply(client, request->handle, ret, 2308 "reading from file failed", errp); 2309 } 2310 2311 if (client->structured_reply) { 2312 if (request->len) { 2313 return nbd_co_send_structured_read(client, request->handle, 2314 request->from, data, 2315 request->len, true, errp); 2316 } else { 2317 return nbd_co_send_structured_done(client, request->handle, errp); 2318 } 2319 } else { 2320 return nbd_co_send_simple_reply(client, request->handle, 0, 2321 data, request->len, errp); 2322 } 2323 } 2324 2325 /* 2326 * nbd_do_cmd_cache 2327 * 2328 * Handle NBD_CMD_CACHE request. 2329 * Return -errno if sending fails. Other errors are reported directly to the 2330 * client as an error reply. 2331 */ 2332 static coroutine_fn int nbd_do_cmd_cache(NBDClient *client, NBDRequest *request, 2333 Error **errp) 2334 { 2335 int ret; 2336 NBDExport *exp = client->exp; 2337 2338 assert(request->type == NBD_CMD_CACHE); 2339 2340 ret = blk_co_preadv(exp->common.blk, request->from, request->len, 2341 NULL, BDRV_REQ_COPY_ON_READ | BDRV_REQ_PREFETCH); 2342 2343 return nbd_send_generic_reply(client, request->handle, ret, 2344 "caching data failed", errp); 2345 } 2346 2347 /* Handle NBD request. 2348 * Return -errno if sending fails. Other errors are reported directly to the 2349 * client as an error reply. */ 2350 static coroutine_fn int nbd_handle_request(NBDClient *client, 2351 NBDRequest *request, 2352 uint8_t *data, Error **errp) 2353 { 2354 int ret; 2355 int flags; 2356 NBDExport *exp = client->exp; 2357 char *msg; 2358 size_t i; 2359 2360 switch (request->type) { 2361 case NBD_CMD_CACHE: 2362 return nbd_do_cmd_cache(client, request, errp); 2363 2364 case NBD_CMD_READ: 2365 return nbd_do_cmd_read(client, request, data, errp); 2366 2367 case NBD_CMD_WRITE: 2368 flags = 0; 2369 if (request->flags & NBD_CMD_FLAG_FUA) { 2370 flags |= BDRV_REQ_FUA; 2371 } 2372 ret = blk_pwrite(exp->common.blk, request->from, data, request->len, 2373 flags); 2374 return nbd_send_generic_reply(client, request->handle, ret, 2375 "writing to file failed", errp); 2376 2377 case NBD_CMD_WRITE_ZEROES: 2378 flags = 0; 2379 if (request->flags & NBD_CMD_FLAG_FUA) { 2380 flags |= BDRV_REQ_FUA; 2381 } 2382 if (!(request->flags & NBD_CMD_FLAG_NO_HOLE)) { 2383 flags |= BDRV_REQ_MAY_UNMAP; 2384 } 2385 if (request->flags & NBD_CMD_FLAG_FAST_ZERO) { 2386 flags |= BDRV_REQ_NO_FALLBACK; 2387 } 2388 ret = 0; 2389 /* FIXME simplify this when blk_pwrite_zeroes switches to 64-bit */ 2390 while (ret >= 0 && request->len) { 2391 int align = client->check_align ?: 1; 2392 int len = MIN(request->len, QEMU_ALIGN_DOWN(BDRV_REQUEST_MAX_BYTES, 2393 align)); 2394 ret = blk_pwrite_zeroes(exp->common.blk, request->from, len, flags); 2395 request->len -= len; 2396 request->from += len; 2397 } 2398 return nbd_send_generic_reply(client, request->handle, ret, 2399 "writing to file failed", errp); 2400 2401 case NBD_CMD_DISC: 2402 /* unreachable, thanks to special case in nbd_co_receive_request() */ 2403 abort(); 2404 2405 case NBD_CMD_FLUSH: 2406 ret = blk_co_flush(exp->common.blk); 2407 return nbd_send_generic_reply(client, request->handle, ret, 2408 "flush failed", errp); 2409 2410 case NBD_CMD_TRIM: 2411 ret = 0; 2412 /* FIXME simplify this when blk_co_pdiscard switches to 64-bit */ 2413 while (ret >= 0 && request->len) { 2414 int align = client->check_align ?: 1; 2415 int len = MIN(request->len, QEMU_ALIGN_DOWN(BDRV_REQUEST_MAX_BYTES, 2416 align)); 2417 ret = blk_co_pdiscard(exp->common.blk, request->from, len); 2418 request->len -= len; 2419 request->from += len; 2420 } 2421 if (ret >= 0 && request->flags & NBD_CMD_FLAG_FUA) { 2422 ret = blk_co_flush(exp->common.blk); 2423 } 2424 return nbd_send_generic_reply(client, request->handle, ret, 2425 "discard failed", errp); 2426 2427 case NBD_CMD_BLOCK_STATUS: 2428 if (!request->len) { 2429 return nbd_send_generic_reply(client, request->handle, -EINVAL, 2430 "need non-zero length", errp); 2431 } 2432 if (client->export_meta.count) { 2433 bool dont_fragment = request->flags & NBD_CMD_FLAG_REQ_ONE; 2434 int contexts_remaining = client->export_meta.count; 2435 2436 if (client->export_meta.base_allocation) { 2437 ret = nbd_co_send_block_status(client, request->handle, 2438 blk_bs(exp->common.blk), 2439 request->from, 2440 request->len, dont_fragment, 2441 !--contexts_remaining, 2442 NBD_META_ID_BASE_ALLOCATION, 2443 errp); 2444 if (ret < 0) { 2445 return ret; 2446 } 2447 } 2448 2449 if (client->export_meta.allocation_depth) { 2450 ret = nbd_co_send_block_status(client, request->handle, 2451 blk_bs(exp->common.blk), 2452 request->from, request->len, 2453 dont_fragment, 2454 !--contexts_remaining, 2455 NBD_META_ID_ALLOCATION_DEPTH, 2456 errp); 2457 if (ret < 0) { 2458 return ret; 2459 } 2460 } 2461 2462 for (i = 0; i < client->exp->nr_export_bitmaps; i++) { 2463 if (!client->export_meta.bitmaps[i]) { 2464 continue; 2465 } 2466 ret = nbd_co_send_bitmap(client, request->handle, 2467 client->exp->export_bitmaps[i], 2468 request->from, request->len, 2469 dont_fragment, !--contexts_remaining, 2470 NBD_META_ID_DIRTY_BITMAP + i, errp); 2471 if (ret < 0) { 2472 return ret; 2473 } 2474 } 2475 2476 assert(!contexts_remaining); 2477 2478 return 0; 2479 } else { 2480 return nbd_send_generic_reply(client, request->handle, -EINVAL, 2481 "CMD_BLOCK_STATUS not negotiated", 2482 errp); 2483 } 2484 2485 default: 2486 msg = g_strdup_printf("invalid request type (%" PRIu32 ") received", 2487 request->type); 2488 ret = nbd_send_generic_reply(client, request->handle, -EINVAL, msg, 2489 errp); 2490 g_free(msg); 2491 return ret; 2492 } 2493 } 2494 2495 /* Owns a reference to the NBDClient passed as opaque. */ 2496 static coroutine_fn void nbd_trip(void *opaque) 2497 { 2498 NBDClient *client = opaque; 2499 NBDRequestData *req; 2500 NBDRequest request = { 0 }; /* GCC thinks it can be used uninitialized */ 2501 int ret; 2502 Error *local_err = NULL; 2503 2504 trace_nbd_trip(); 2505 if (client->closing) { 2506 nbd_client_put(client); 2507 return; 2508 } 2509 2510 req = nbd_request_get(client); 2511 ret = nbd_co_receive_request(req, &request, &local_err); 2512 client->recv_coroutine = NULL; 2513 2514 if (client->closing) { 2515 /* 2516 * The client may be closed when we are blocked in 2517 * nbd_co_receive_request() 2518 */ 2519 goto done; 2520 } 2521 2522 nbd_client_receive_next_request(client); 2523 if (ret == -EIO) { 2524 goto disconnect; 2525 } 2526 2527 if (ret < 0) { 2528 /* It wans't -EIO, so, according to nbd_co_receive_request() 2529 * semantics, we should return the error to the client. */ 2530 Error *export_err = local_err; 2531 2532 local_err = NULL; 2533 ret = nbd_send_generic_reply(client, request.handle, -EINVAL, 2534 error_get_pretty(export_err), &local_err); 2535 error_free(export_err); 2536 } else { 2537 ret = nbd_handle_request(client, &request, req->data, &local_err); 2538 } 2539 if (ret < 0) { 2540 error_prepend(&local_err, "Failed to send reply: "); 2541 goto disconnect; 2542 } 2543 2544 /* We must disconnect after NBD_CMD_WRITE if we did not 2545 * read the payload. 2546 */ 2547 if (!req->complete) { 2548 error_setg(&local_err, "Request handling failed in intermediate state"); 2549 goto disconnect; 2550 } 2551 2552 done: 2553 nbd_request_put(req); 2554 nbd_client_put(client); 2555 return; 2556 2557 disconnect: 2558 if (local_err) { 2559 error_reportf_err(local_err, "Disconnect client, due to: "); 2560 } 2561 nbd_request_put(req); 2562 client_close(client, true); 2563 nbd_client_put(client); 2564 } 2565 2566 static void nbd_client_receive_next_request(NBDClient *client) 2567 { 2568 if (!client->recv_coroutine && client->nb_requests < MAX_NBD_REQUESTS) { 2569 nbd_client_get(client); 2570 client->recv_coroutine = qemu_coroutine_create(nbd_trip, client); 2571 aio_co_schedule(client->exp->common.ctx, client->recv_coroutine); 2572 } 2573 } 2574 2575 static coroutine_fn void nbd_co_client_start(void *opaque) 2576 { 2577 NBDClient *client = opaque; 2578 Error *local_err = NULL; 2579 2580 qemu_co_mutex_init(&client->send_lock); 2581 2582 if (nbd_negotiate(client, &local_err)) { 2583 if (local_err) { 2584 error_report_err(local_err); 2585 } 2586 client_close(client, false); 2587 return; 2588 } 2589 2590 nbd_client_receive_next_request(client); 2591 } 2592 2593 /* 2594 * Create a new client listener using the given channel @sioc. 2595 * Begin servicing it in a coroutine. When the connection closes, call 2596 * @close_fn with an indication of whether the client completed negotiation. 2597 */ 2598 void nbd_client_new(QIOChannelSocket *sioc, 2599 QCryptoTLSCreds *tlscreds, 2600 const char *tlsauthz, 2601 void (*close_fn)(NBDClient *, bool)) 2602 { 2603 NBDClient *client; 2604 Coroutine *co; 2605 2606 client = g_new0(NBDClient, 1); 2607 client->refcount = 1; 2608 client->tlscreds = tlscreds; 2609 if (tlscreds) { 2610 object_ref(OBJECT(client->tlscreds)); 2611 } 2612 client->tlsauthz = g_strdup(tlsauthz); 2613 client->sioc = sioc; 2614 object_ref(OBJECT(client->sioc)); 2615 client->ioc = QIO_CHANNEL(sioc); 2616 object_ref(OBJECT(client->ioc)); 2617 client->close_fn = close_fn; 2618 2619 co = qemu_coroutine_create(nbd_co_client_start, client); 2620 qemu_coroutine_enter(co); 2621 } 2622